java，课堂练习，

import java.util.Scanner;

public class a {

	public static void main(String[] args) {
		for(int j=1;;j++){
		Scanner sc=new Scanner(System.in);
		System.out.println("请输入年龄：");
		int i=sc.nextInt();
		int a=23;
		if(i<0||i>110)
		{
			System.out.println("输入错误！请重新输入！");
		}else if(i>a)
			{
				System.out.println("猜大了");
			}else if(i<a)
			{
				System.out.println("猜小了");
			}else
			{
				System.out.println("猜对了");
				break;
				
				}
		}
	}
}